DataSnapShot.value == null

[mgoodwin14]

given this sample(in kotlin):

fun getIsLiked(query: DatabaseQuery): Maybe<Boolean>{
    return RxFirebaseDatabase.observeSingleValueEvent(query, 
        {snapShot -> (snapShot.value as Long).toInt() == 1})
}

I had an issue where the value was null. (which happens if it isn't in firebase)
I wasn't able to find a work around using this function with a mapper.
Instead, I used the single parameter call and did:

.filter( { snapShot -> snapShot.exists() } )

Not sure if this is by design or not but I don't think an empty DataSnapShot should be emitted?

My suggestion change source from

public void onDataChange(DataSnapshot dataSnapshot) {
    emitter.onSuccess(dataSnapshot);
    emitter.onComplete();
}

to

public void onDataChange(DataSnapshot dataSnapshot) {
    if(dataSnapshot.exists())
        emitter.onSuccess(dataSnapshot);
    emitter.onComplete();
}

Just my 2 cents.

P.S. great library, found this to be most helpful.